Electromagneto energy conversion



pt. 25. 1956 E. G. JOHNSON 2,764,721

ELECTROMAGNETO ENERGY CONVERSION Filed June 9, 1952 MAGNETIC PARTICLES IN OIL ill MAGNETO-TRACTIVE FLUID INV EN TOR.

United States Patent 2,764,721 ELECTROMAGNETO ENERGY CONVERSION Ervin G. Johnson, Oakland, Calif., assignor to Eleanor de Hass Johnson, Oakland, Calif.

Application June 9, 1952, Serial No. 292,407 Claims. (Cl. 318-161) This invention is in electrical energy conversion.

It is one of the objects of the invention to provide improved methods of converting energy from electrical to mechanical manifestations.

Other objects and advantages will be evident from a consideration of the following description with reference to the accompanying drawings, in which:

Fig. 1 shows schematically apparatus for energy between rotating masses;

Fig. 2 is a fragmentary section transverse the axis of components of kinetic energy translating apparatus.

Fig. 3 is a section transverse the axis of a magnetokinetic energy engine; and

Fig. 4 is a modified form of the device shown in Fig. 2.

Referring to Fig. l, the apparatus comprises an electric motor driving a shaft 12 carrying slip rings 14 joined by a conductor including a solenoid winding 16 about a ferromagnetic core portion of shaft 12 between two annular magnetic pole forming rings 18 magnetically integral with the core portion and forming therewith an annular groove within which is fixed for rotation with the shaft an energy interchanging assembly comprising a closed hollow housing 20 formed as of two radial discs 22 and two concentric cylinders 24 and 26, the housing being formed preferably of non-ferromagnetic material such as rubber, aluminum, glass, plastic, brass, or the like. The housing forms a closed annular chamber within which there is placed a magneto-responsive fluid or semi-fluid suchas ferro-magnetic particles in oil, similar to that employed in magnetic particle clutches and brakes. s

The behaviour of the apparatus is somewhat as follows. Upon applying voltage to the lines L current flows through the motor 10 and winding 16 thus forming a magnetic field between the poles 18 and causing the shaft 12 to be rotated by the motor 10. The initial current flow is usually large because of the initial low impedance of the circuit. The iron particles in the oil are drawn into the magnetic field between poles' 18 adjoining the inside surface of wall 24. The moments of inertia of these particles is thereby minimized yet their motion peripherally is resisted or arrested with respect to the shaft by the magnetic field. The high current and resulting low gross inertia allows a more rapid initial acceleration of shaft 12 to speeds of shaft 12 at which motor 10 efliciently translates electrical energy into mechanical kinetic energy. As the shaft speed reaches higher values the impedance increases and the current flow decreases while at the same time the centrifugal force on the particles increases. The magnetic field between poles 18 decreases with the decrease in current flow and the magnetic particles tend to move radially outward toward wall 20, as well as tending to slip back with reference to the shaft.

As shown in Fig. 2, the housing 20 may be provided with axial vanes such as 30 and 32 extending radially from the cylinders and between walls 22. These tend to prevent slippage of the particles peripherally. A peripheral escape channel 34 may be provided between the vane tips whereby some slippage is introduced.

Assume that, normally, the motor 10 operates at a fixed speed. When a sudden load is applied to shaft 12 the motor 10 slows down abruptly and a surge of curinterchanging "ice rent passes therethrough tending to resist the further slowing thereof. This current draws the magnetic particles in housing 20 radially inward, thus causing them to deliver part of their kinetic energy to the vanes 30 and thereby assisting the motor 10 to resist the slowing of shaft 12.

Most motors 10 have a maximum speed under given load conditions. In order to increase the speed of shaft 12 beyond this speed momentarily, an auxiliary winding 16 is provided about the magnetic core portion of shaft 12, such auxiliary winding being provided for large current carrying capacity or to provide for a large ampere turn product. Through winding 16 a current may be passed while the motor rotates so as to cause the iron particles to be drawn toward the shaft and in doing so to impart part of their kinetic energy to the vanes 30 for increasing the shaft speed, or for maintaining the speed when a load increases. Such may be effected in response to motor load current acting on a suitable control for increasing the current through such winding 16. It is believed to be clear that, in the absence of vanes 30 and 32 the magnetic particles are controlled only by the wall friction and the magnetic and centrifugal forces if any, wherefore, when not magnetized they form little resistance to starting and deceleration.

In Fig. 2 the housing 20' is shown surrounded by an electromagnetic structure 36 of somewhat conventional design and including the magnetic core and phase windings with which to produce the familiar effect of a rotating magnetic field around the periphery of housing 20'. Considering the structure 36 to be stationary, the rotation of the magnetic field, depending upon its sense with regard to the rotation of shaft 12, accelerates or retards the housing 20' by magnetic pull on the particles of iron therein. The magnitude of the pull is influenced by the current in windings at 16 or 16 on the core part of shaft 12.

The apparatus of Fig. 3 comprises laminated magnetic iron core structure rigidly mounted on a shaft 12 and providing a continuous magnetic gap in the core structure between poles of the structure which gap is occupied by a wholly closed ring shaped envelope 41), or housing, formed of non-ferromagnetic material such as rubber, ceramic, porcelain, glass, plastic, or a metal of low mag netic induction.

A housing 40 may have a rectangular cross section in planes including the axis of shaft 12 and, as shown, may have the concentric walls thereof each formed in a wavy peripheral and continuous closed curved surface, the purpose of the variation in radial distances of the walls being to provide tractive engagement of fluid contained by the housing,

though circularly cylindrical concentric walls provide considerable traction also. The housing is substantially filled with a magneto-tractive fluid such as a mixture of iron particles and oil, or a fluid metal such 3S mercury.

The magnetic core structure may comprise two concentric core groups of almost standard iron laminations 42 and 44 having facing axial conductor slots 46 for the reception of phase winding conductors 47 corresponding for example to the windings of the rotor and stator of a plural phase wound rotor induction motor. The concentric core groups 42 and 44 are rigidly held on the shaft 12 by suitable spiders or the like, not shown, in such a way that, preferably, substantially all magnetic flux from each pole produced by registering pole windings in the pass radially through housing 40 in accordance with well understood and known principles. The windings are excited from alternating current sources of electricity, usually of the polyphase source type, slip rings being carried by the shaft 12 for the conduct of current to the windings in slots 46, both the windings on the core group 42 and those on the core 44 being fed from the same slip rings, either in series or in parallel and connected in such manner that phase pole windings in opposite areas of cores 42 and 44 produce magnetomotive forces in the same sense through the housing 40 and adjoining core 'fiu'x paths. Eachfpb'l'e pair formed by and between the core groups 42 and '44 has a similar gap filled by the housing 40.

With the housing 49 filled with oil and iron magnetic particles, upon the occurrence of the rotating magnetic field in the housing, the magnetic particles tend to -forin radial bridges from wall to wall between the "groups '42 and '44 which bridges tend to slide peripherally with the magnetic field, but behaving somewhat as a 'fl'u'id and pushing against the walls 'of 40 in 'a tangential sense to impart rotationto the housing, cores, and shaft'I'Z.

It is to be observed that the rotating magnetic 'ii'eld has a rotational speed with respect to the shaft determined by the number of magnetic poles for which 'the cores are wound, and the frequency. The speed of the particles with respect to the shaft tends 'ttiwardthe speed of the magnetic rotating field with respect to the shaft, and the particles have absolute speed with respect to earth which is always greater than the shaft speed with respect to earth. The tangential acceleration of the particles is proportional to the 'rnagnetomotive force of the windings and, in turn, to the applied current in the windings. It will be seen that the acceleration of the particles causes them to push on the Walls of 40 in the tangential sense, causing the same to move in the direction of rotation of the magnetic field. The angular velocity of the magneticfield with respect to earth, is, then, equal to the sum of: the speed of the shaft and the speed of the field with respect to the shaft. The particles therefore receive the same acceleration at all speeds of the shaft, the current and frequency being constant.

It is to be observed that the entire structure becomes an inertia wheel or flywheel, and may itself be mounted within a working body, such as within a gear, a pulley wheel, a grinding wheel, a vehicle wheel such as in the landing wheels of aircraft, a pump rotor for centrifugal and like pumps, a lathe chucking plate, a propeller or fan, and the like, thus allowing shaft 12 to be 'very short, sufiicientonly to provide adequate bearing support for radial thrust, with very little length of shaft devoted to transmission of power. The shaft 12 may, beyond its bearings, be 'flexible "and be hollowfor the passage therein of the conductors from slip "rings 'at any distancealong its axis.

A second type of "energy translating device isa modi fiedconventional'electricmotor wherein the motive action is conveniently produced by a rotating magnetic field across a somewhat conventional axial air gap instead of a somewhat-cylindrical 'air gap 'such'as in Fi'g. 3. A section through the mag'neto-tra'ctive fluid housing employed is shown in Fig. 4- to comprise somewhat spiral vanes. The radial position of the magneto-tractive'fluid in the compartments between the vanes and'radial side walls may becontrolled by both or either of means corresponding to the winding 16 in Fig. 1, and the rotating magnetic field'windings of the axial air gaptype, whether carried in core structure for rotation with the housing as -in Fig. 3, ors'tationary'adjacent'thereto'as in Fig.2.

It will be observed that the direction-o'fthe'vanes as respects rotational direction influences the functions. If, inFig. 4, the rotation is to be anti-clockwise, starting with only'the rotating magnetic fleldte'ndsto bring "the fluid toward the center thus producing a more rapid acceleration. When running, a sudden increase in'speed of the rotating magnetic field as by decreasing the frequency of the current causes the fluid to move radially inward and to deliver some of its kinetic 'energ'ytothe vanes. A sudden decrease in speed of the magnetic field causes the fluid to instantly decelerate the rotor by developing instantly a maximum decelerative torque.

If the rotation in Fig. 4 is clockwise, at starting the vanes themselves assist centrifugal force and the field in radiating the fluid and initiating more rapid storage of kinetic energy therein and less acceleration to the shaft. At any speed a sudden increase in magnetic field speed is instantly "and directly effective onthe rotor to accelerate it, without yielding any of the fluid kinetic energy to the shaft. However, by exciting the Winding 16, the kinetic energy of the fluid may be transmitted into the shaft partially, while the fluid moves radially inward over the convex surfaces of the vanes. Deceleration is more pronounced when the rotating magnetic field speed is rapidly decreased or reversed since the energy of the fluid is given up against the concave surfaces of the vanes in the brakingeflort.

'For some purposes holes may be placed through the vanes adjacent the inner and/or the outer radial ends thereof so "that the fluid may escape peripherally therethrough at a desired rate. Moreover, two sets of opposite'ly directed vanes in separate housings on the same shaft and, 'permissibly, in 'the same air gap, may be associated with controls for the elective diversion of the fluid from one to the other, thus obtaining alternatively the characteristic of either for either direction of rotation of the shaft.

Having thus described various forms of structure embodying my invention and their modes of operation, I claim:

*1. A'variab'le inertia device, comprising: a rotor having formed therein a plurality of radially extending and circumferentially arranged pockets, a magnetic powder in said pockets, and flux producing means arranged to move said powder in said pockets to vary the inertia of said rotor.

'2. A variable inertia device, comprising: a rotor having formed "therein a plurality of radially extending pockets, a'rnixture of liquid and magnetic powder in each of said pockets, and flux producing means arranged to move said powder radially in said pockets to vary the inertia ef'sai'd rotor.

3. The combination of claim 2 in which said pockets are of such an 'extent'that as the radial displacement of said po'w'der is'reduced the inertia of saidrotor is reduced.

4. A variable inertia device, comprising: a rotor having formed therein a plurality of circumferentially arranged and connected pockets, a mixture of liquid and magnetic powder in said pockets, means establishing a flux -which-moves from pocket to pocket and thereby moves 'said fluid and powder circumfcrentially of said rotor.

5. The combination of claim '2 including: an electric motor, means connecting said motor to said rotor for rotation thereof, and a power connection between said motor and said 'flux producing means, whereby the density of said flux and the radial displacement of said powder willbe a'function of variations in the performance of said motor.

References Cited in the :file of this patent UNITED STATES TATENTS 68,530 Rice Sept. 3, 1867 1,254,694 Humphries Jan. 29, 19-13 1,298,664 Chubb Apr. 1, l9l9 1,630,201 'Metcalf May24, 1927 2061,867 'Muynck Nov. 24, .936 '2,603,103 -Sohon et a1. July 15, 1952 2,605,876 Becker Aug. 5, l952 2,663,809 Winslow Dec. .22, 1953 FOREIGN PATENTS 232,635 Great Britain c .Ju1y..20, 1926 

